Smirnova D.A., MD, PhD, Nosachev G.N., MD, PhD,

Sloeva E.A., PhScC, Krasnov A.N., MD, PhD, Kuvshinova N.Yu.

Samara State Medical University, Russian Federation

Clinical and psycholinguistic study of mild depression

(diagnostic specifity of thinking process)

Depression is a common healthcare problem and, in particular, one of the most important problem of psychiatry. Depression is largely managed in primary care, with little or absence of psychiatrist’s input. The quality of care is often “low, with poor recognition of the condition, inadequate prescription, poor compliance with medication and poor provision and uptake of psychological interventions” [2].

The increased social and economic costs for prevention, diagnosis and therapy of depression makes this mental disorder one of the main problems of modern society [3, 6, 7]. Depression, in particular the mild form, damages the capabilities of adaptation, changes the usual way of life, meaning and quality of life of patients, causes professional and personal difficulties [1, 4, 5]. In order to organize correct management and treatment and control clinical outcomes of mild depression, it is necessary to diagnose this state opportunely.

Data of prevalence and disease incidence of mild depression rapidly grow up both in the system of psychiatric service and primary medical care. Mild depression is still as unrecognized as false-diagnosed amongst healthy persons with a sad mood. Nevertheless, even an experienced specialist has difficulties when diagnoses mild depression. The question is: “Is that a patient with mild depression or a healthy person with a sad mood which was caused by the problem situation in his life?” There’s no any difference in nonverbal behaviour because the mild depression doesn’t demonstrate motor retardation or mutism or total unhedonia in contrast to the moderate and severe depression. The basic method of diagnostics of mental disorders is the method of clinical interview (so called clinical-psychopathological method), which realizes through the verbal interaction between doctor and patient. Verbal structures are proved to be the leading subjective factors of the pathogenesis of mental disorders. There are a number of studies which evidence the presence of psycholinguistic peculiarities of different mental disorders, including depression, and changes of verbal data which correlate with therapy dynamics and recovery. Doctors do not perceive their patients in association with specific lexics of mental disorders still. Speech is the only source of significant information about patient’s mental state when mild depression is diagnosed. Whereas the detailed study of structure and semantics of patients’ speech could clarify the clinical diagnostics by revealing the specific psycholinguistic markers.

124 patients with mild depression and 77 controls, average age 41,85 ±11,89 years (2/3 women), were studied at the moment of the first request for medical help. Depressive state was studied with the use of clinical interview. Depression symptoms were assessed with the depressed mood item from the Hamilton Rating Scale for Depression-21 (HRSD-21). Speech was studied using a number of standard psycholinguistic procedures at the superficial and deep levels. 201 texts written on the theme of the current state of life were investigated. Descriptive methodics, nonparametric analysis (U-criteria Mann-Whitney, test by Wald-Wolfowitz, p<0,05), mathematic modeling of discriminate analysis (λ–Wilks; method Standard) were used in statistics (Statistica 6.0, Statsoft, USA, licensed).

Patients were divided into three clinical groups (melancholic (M, n=38), anxious (A, n=45) and asthenic-hypodynamic (AH, n=41) depressions). Clinical criteria, which correlate with the leading hypotymic affect and contribute to differentiate the types of mild depression, have been clarified. The criteria were the affective component, the semantics of associative component, the leading component of the depressive triad, the vector of the prevailing representation of time.

Table 1

Psychopathological features of clinical types of mild depression

Clinical types of depression Criteria	Melancholic	Anxious	Asthenic-hypodynamic
Affective component	inexpressive melancholy, grief, sadness, despondency LEADING	anxiety, disturbance, emotional agitation, emotional strain	boredom, emotional instability, indifference
Associative component	ideas of guilt, worthlessness, uselessness, semantics of gloom, absence of life sense, offence, self-pity, disappointment	anxious doubts, thoughts, analyzing, prognosing, semantics of strain, tension, uncertainty, getting in a muddle LEADING	ideas of hopelessness, helplessness, uselessness, semantics of lack, extinction or gravity, pressure
Activities and motor component	striving to retire from any active contacts, try to enjoy, to get pleasure	striving to cope with the state, emotions, to get support, to control the events, to protect relatives	hypoergia: lack of strength, fatique, exhaustion; hypodynamia LEADING
Time representation	focus on the past, negative memories	focus on the future, as an unknown and threatening	focus on the present asthenic state, rarely - hopeful future

Data demonstrated that the structure of the leading affect has an influence on the whole structure of mild depression, in particular, forms a leading component of triad.

Patients with mild depression observed certain clinical and psycholinguistic features. Speech was distorted both in structure and semantics. The most pronounced changes in speech, which affected mainly deep structures, were occurred in M. Superficial level of speech was mostly damaged in AH. Speech was similar to healthy and reflected the resource signs in A.

Psycholinguistic features of patients with mild depressions expressed distortion not only of the content but also the structure of thinking. Representative strategy of cognition, presence of successive judgments and rare abstract and reasoning constructs were noted in M. Missing of words and facts, more frequent abstract judgments and incompleteness inside the judgments while maintaining the overall coherence of context were specified for AH. Increasing coherence of facts, more frequent reasoning judgments, strengthening of semantic interrelationship between following judgments, preferential strategy of explanation were observed in A type.

Data revealed the distortion of structure and semantics of speech in patients with mild depression which testified the most pronounced psychopathological disorders of thinking at M type and higher resources of ideation at A depressive state.

Mathematic modeling confirmed the significance of verbal markers and specify of thinking process for diagnostics of clinical types of mild depression and independent subgroup of healthy with problems (98%).

The results support the concept that psycholinguistic characteristics both of structure and semantics of speech may be a useful indicator for mild depression. Psycholinguistic features remains an independent indicator of mild depression and normal sadness and could be even taking into account as the core symptom of mild depression when reflects and correlates with associative component’ of thinking process’ distortion which is the main for diagnostics of this kind of mental pathology.

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